Can EMG help identify muscular co-contraction in people with dystonia?This study tests whether the use of a portable muscle biofeedback device helps children learn to relax dystonic muscles, or to contract weak or neglected muscles. Children wear a battery-powered device on their arm that vibrates in response to muscle contraction for at least 5 hours per day every day for one month. At the beginning and end of the month the quality of arm movement is tested in the laboratory using motion-capture equipment. (clinicaltrials.gov registration NCT00473161)

Disorders of Motor Learning in Children with Dyskinetic Cerebral PalsyThis study tests the speed of motor learning using two methods: (1) the time needed to adapt to forces applied to the hand by a robot during movement; (2) the ability to use arm muscles to control a computer when the computer response to the arm muscles changes rapidly. (clinicaltrials.gov registration NCT00285870)

Mechanisms that Impair Movement in Children and Young AdultsThis study tests whether children with dystonia and dyskinetic cerebral palsy have difficulty learning to move individual muscles because of problems with perception of muscle patterns or lack of experience with successful movement. Control of muscles in the hands and arms is assessed while children attempt to use these muscles to control a computer. Barriers to successful learning are assessed by measuring improvement in control when children are provided with additional information about the tasks. (clinicaltrials.gov registration NCT00285870)

Quantification of Upper Extremity Dystonic Hypertonia in Children and Young AdultsThis study measures the stiffness of the elbow and the reflex responses of muscles that cause the stiffness. Stiffness is measured either by measuring the force required for an examiner to pull on the arm, or by using a robot that pushes or pulls the elbow either while it is at rest or during attempts at movements. (clinicaltrials.gov registration NCT00285870)

Abnormalities in Upper Extremity Kinematics in Children with Hyperkinetic Cerebral PalsyThis study uses motion capture equipment to measure the arm movements of children with hyperkinetic cerebral palsy while they are reaching to targets. It attempts to describe different types of abnormal arm movements that may be used to predict the effect of treatments on particular children.

Measuring Kinematics in a Clinical SettingThis study uses a portable motion capture system to measure the arm movements of children.

Quantitative Measurements of Limb Stiffness in ChildrenThis study uses a portable stiffness-measuring system to measure arm and leg stiffness and strength in children with hypertonia and/or weakness.